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enCopyright 20162016-12-05T14:37:08+00:00Understanding Evolution&mdash;Naming Matters but Not That MuchThu, 28 Jan 2016 13:05:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/understanding_evolution_naming_matters_but_not_that_much
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The arguments go like this: “If Archaeopteryx is classified as a bird, then it isn’t a dinosaur, and you can’t say that birds came from dinosaurs.” Or, “Since Tiktaalik is classified as a fish, it can’t be the missing link between fish and amphibians.” Those of us with training in biology sigh, because this is a horrible misunderstanding of how classification works.

Taxonomy—Classification and Naming Species

One of the first things I teach in any of my paleontology classes is that taxonomy underpins nearly every subdiscipline of paleontology. I then go on to explain that taxonomy is also very subjective and, at times, even seemingly arbitrary.

So then, what is Taxonomy?

Taxonomy is the study of naming or classifying organisms. It is the proper use of scientific names. Taxonomy is why every scientist on Earth, regardless of his or her native tongue, knows that the name Homo sapiens refers to humans.

Thus, taxonomy is important, as it ensures that everyone uses the same name for the same species of organism, despite what word they might use in their local language. In principle anyway.

Taxonomy becomes a challenge where you have distinct species that can interbreed (for example, dogs, wolves, and coyotes). Are they one species or many? Such questions spur discussion at scientific meetings, and biologists work hard to come up with a better definition of the concept of species.

In the case of fossils, we cannot observe behaviors, breeding compatibilities, or distinctions between the forms of males and females of the same species—all of which we know can help us distinguish different species in living organisms. All we have are shapes and sizes of skeletons and occasionally some remains of soft tissues. As paleontologists, we have to decide what differences are sufficient to make two species distinct.

This process is subjective, dependent upon the experience, expertise, and general preference of the paleontologist. One paleontologist may see three different species from two different families, and another may think that they’re all members of the same species with a lot of variability in form. Or that some are male and others are female. Or that some represent juveniles and others adults.

Nevertheless, taxonomy is fundamentally important in paleontology. When paleontologists name new species, they must follow very strict rules to ensure that their new species is valid or acceptable by the rest of the paleontological community. A group of scientists—not just paleontologists but also zoologists—have formed the International Commission on Zoological Nomenclature (ICZN), to ensure that when new species of animals are named it is with good reason. If you’ve ever read a technical paper that names a new species, you’ll notice that it very carefully describes the new species and distinguishes the new species from similar species.

Even with this process, paleontologists may yet argue whether two species are really different or not. For example, the debate about Triceratops and Torosaurus: Some paleontologists think that Triceratops is just a young Torosaurus. Others argue that they are definitely different species.

The fundamental question is does it matter?

The answer is yes!

Even though we might not agree about the details of one species or another, by carefully naming species, we as paleontologists can always be confident that we’re talking about the same organisms by using the scientific names of animals that were named following the rules put forth by the ICZN. In later research, scientists can specify what they mean when they are talking about a particular species. They can specify if they consider Triceratops and Torosaurus the same, or if they believe that they are just closely related species.

Once this is clearly laid out, paleontologists can approach the real questions they want to explore.

Phylogeny—Relationships among Species

Much of paleontology focuses on the evolutionary relationships among fossils and modern species. Fundamentally, we want to know where we came from. This is phylogeny.

In some ways, taxonomy reflects phylogeny. All the mammals are in one group (Class Mammalia) because they’re all related. We put all the birds together (Class Aves). Bigger groups, such as the Class Mammalia, are divided into smaller groups, the Family Equidae (which includes horses, donkeys, and zebras) or Family Canidae, the Dogs (includes wolves, foxes, and our pet dogs). All the members of such taxonomic groups are (presumably) closely related. (This is not always the case, however, and is a worthy topic for later posts.)

The only taxonomic division that has a clear definition is that of species, which as noted above can only be applied to a new animal when certain rules, laid out by the ICZN, are followed. All the other taxonomic groupings, so-called “higher taxa” such as Family, Order, and Class, are considerably more subjective. They exist for convenience to help us keep our thinking on organisms organized, but they have little basis in the reality of the relationships among living things. There’s no defined number of species that need to be grouped to make a Family, nor is there any specified amount of difference needed to place species in different families or classes.

The fossil record provides abundant evidence of where smaller groups (like Family) came from within the larger groups (like Order), but the ancestors of the smaller groups often aren’t terribly similar to the more modern members of the group. For example, horses came from animals that were not particularly horse-like, so how do we classify them? The vast majority of paleontological research shows that birds came from a group of dinosaurs that weren’t birds at all, though they do have many features in common. How do we classify these?

Classifying such organisms into higher categories is difficult. But the classification (the taxonomy), aside from species, does not affect the actual relationships (the phylogeny), because taxonomy and phylogeny are not the same thing. For example, it doesn’t matter if Archaeopteryx is classified as a bird or a dinosaur. What matters is that Archaeopteryx as a species is clearly defined and distinct from other dinosaurs and other birds. Then we can start to understand how it is that birds and dinosaurs are hardly different in some ways but utterly different in others.

Taxonomy is important insofar as the species must be clearly defined. The ICZN does a good job of making sure this is the case, though it can get very complex. For modern organisms, species can be defined by behavioral or reproductive patterns that are seldom preserved in the fossil record. In paleontology, we rely entirely on the shape and size of fossils to distinguish species. Nevertheless, provided a species is defined carefully, it is useful for the study of phylogenetic relationships.

Phylogeny is dependent on species—whether modern or fossil—being clearly defined so we can explore the similarities and differences among species and work out evolutionary relationships. This is done typically through cladistic analysis, which is essentially a mathematical means of exploring similarity between species, assuming that those more similar are likely to be more closely related (but this is an oversimplification and is a topic of another post).

To even begin to discuss phylogeny, we must understand taxonomy, particularly the concept of species. Thus, taxonomy underpins all study of the evolutionary relationships among organisms.

]]>On Biblical KindsFri, 19 Dec 2014 11:10:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/on_biblical_kinds
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There are several alternative hypotheses offered by theists to counter the scientific theory of evolution. These tales of special creation generally posit
that all organisms on this planet were placed here, in their current form, by a supernatural entity. Perhaps the most familiar of these is the idea of
Intelligent Design (ID), which has been put forward as scientific, and worthy of inclusion in science classrooms. ID is a Christian concept, based largely
on literal interpretations of the Bible, though it does not necessarily restrict itself to a young (6000-year-old) Earth.

The basic concept of Bible-based creationism is that the major groups of living organisms on this planet appeared on the fifth and sixth days, as described
in the book of Genesis in the Bible. Since then, the mechanisms of Evolution—specifically microevolution—have taken place within these major groups,
resulting in the diversity of species within these groups we recognize today.

These major groups of organisms are referred to as “kinds” in the Christian creationist model. “Kinds” are different groups of organisms that seem
intuitively distinct from other groups. For example, horses, donkeys, and zebras may belong to a single kind, the horse kind. There is a dog kind, that
includes wolves and coyotes, too, and foxes for good measure. There would be kinds of trees, like oaks or maples. The assumption is that from these basic
kinds comes all the modern diversity, like pin oaks, live oaks, and scrub oaks. All of life is thus divided into the kinds that originated at Creation.

Advocates of Biblical creationism stress that the “kinds” are unique, and that there are no intermediate forms to be found between them. Further, they
believe that kinds can be proven to be real using scientific methods.

So a “kind” is the basic division of organisms according to Creationists, in much the same way that “species” is the fundamental division of organisms to
evolutionary biologists. The theory of evolution explains how evolution occurs within species, and over vast amounts of time, results in new species. Over
even longer periods of time—millions or billions of years—new larger groups of organisms, similar to kinds, can evolve. The origin of these new, larger
groups is a process called macroevolution. Proponents of biblical creation claim that macroevolution is impossible because the kinds are distinct
and always have been. No new kinds have ever arisen since they were created.

So, then, what is a kind?

I’ve asked this question more than once, most often to students wishing to explore the Creationism vs Evolution debate. I’ve never gotten a very satisfying
definition. In February of 2014, Ken Ham (Creationist and Founder of Answers in Genesis) finally provided a working definition during his debate with Bill
Nye. Ham said that kinds are groups of animals at about the same level of scientific classification as “family.”

Family is a scientific term in the field of taxonomy (the science of naming and classifying organisms) that is a group that includes many species, both
closely related and more distantly related. For example, the family equidae includes horses, zebras, and donkeys. The family canidae
includes dogs, and coyotes, and wolves. It also includes foxes, which are more distantly related and not in the genus canis. There’s the familysuidae, the pigs. Peccaries are pig-like, but wait, they’re in the family tayassuidae. Hm. Well, they’re both in the suborder suina, so maybe that’s what Ham meant when he said ‘about the same level as family.’

At a first pass it seems, at least with commonly known organisms (focusing on mammals), that this idea that a biblical kind could be roughly equivalent to
a scientific family.

Let’s back up, because there’s a falsehood here. Just because taxonomic nomenclature is used by scientists, doesn’t necessarily mean there isn’t some
arbitrariness there. The scheme that includes family was created by Linneaus in 1751. Families in the Linnaean sense were groups of animals that seemed
similar enough to each other to be related. But there was no biological basis for this. It was just done that way because it felt right. It is rather
subjective, and based, to a large degree on what seems right—just like the concept of kinds.

As science has progressed, it has become clear that many of the groups proposed by Linneaus are arbitrary. In fact, as we’ve come to understand biological
evolution, scientists are using Linnaean nomenclature less and less for discussion of evolution. Instead, scientists opt to use more rigorous methods, like
cladistic analysis, to explore evolutionary relationships. Linnaean taxonomy merely hangs on as a convenient way to name and categorize organisms, but it
is no longer used to support actual relationships between organisms.

The only place where Linnaean taxonomy retains a strong foothold (and for how much longer one cannot be sure) is in the naming of species. Species is the
only Linnaean rank with a specific and clear definition. In biology, it is required for a species to be able to reproduce with other members of its species
and produce viable fertile offspring. Every other grouping is made for convenience, and the ranking (genus, family, etc.) is determined based on the
researchers subjective determination of how similar or different groups are from one another.

Higher ranks (genus, family, order, etc. all but species) are subject to change. The definition of such a group may be revised. Its rank may change. The
members of the group may be changed. Most often, such things happen with either the discovery of new species, or due to new methods for determining
relationships

Take, for example, the mustelidae—the weasel family. Traditionally skunks, minks, weasels, badgers, otters, and wolverines are in this family.
They do look a lot alike, low to the ground, long in body, carnivorous, smelly. But genetically, skunks are distinct. In fact, they are more different
genetically from the other members of the mustelidae than are seals and raccoons, which clearly are not mustelids.

Or take, for another example, the matter of the giant panda (Ailuropoda melanoleuca). There has been a lot of discussion in the biological
community about whether or not the giant panda is a true bear, and should be assigned to the family ursidae with all the other bears. It certainly
looks bear-like, hence the colloquial name of ‘panda bear,’ but it also is fully herbivorous which is notably not-bear-like. That might be just fine, given
that although the family ursidae is within the order carnivora, the carnivorous mammals, the only fully carnivorous member of the ursidae is the polar bear.

Giant pandas share much in common with both bears (family ursidae) and raccoons (family procyonidae). Based only upon physical
characteristics alone (not all of which are obvious to an untrained observer), we couldn’t really be certain to which group giant pandas belong. These are
two very different groups of mammals that are clearly distinct (as ‘kinds’ are supposed to be), and the giant panda could go either place. For what it’s
worth, we’ve learned that pandas are properly bears, based on DNA analysis (see O’Brian et al., 1985).

Red pandas (ailurus fulgens) have suffered similarly. They are definitely not bears, but may or may not be related to raccoons. Again, genetic
evidence provides the solution and places them in their own family separate from raccoons and bears (O’Brian et al., 1985)

We know about the flexibility, arbitrariness, and inaccuracies of taxonomic groups as practicing biologists and paleontologists. But for the general public
it's not so clear. Evolution is not well taught in classrooms around the nation. All students are given is Linnaean taxonomy, and the impression that it’s
the most scientific thing out there. So of course it sounds really scientific to say kinds are at the same level as family to everyone except those who
really understand biology.

To biologists, to say that kinds and families are equivalent is to say that kinds are completely arbitrary and grouped according to whatever feels right.
This is no improvement over the definitions I’ve gotten in the past and is still unsatisfying.

But at least it sounds science-y and tastes pretty good, like the bologna that it is.

The point to all of this is that the term “kind” is still poorly defined. Saying it’s at about the level of family seems helpful and valid; however, the
concept of a family in the Linnaean sense is amazingly arbitrary. These are defined as groups of animals that seem to be related to each other—which is
basically the same as the definition of a kind in the first place.

When tested rigorously using cladistic methods, and even only on modern organisms, the arbitrariness of all the Linnaean ranks becomes clear. They’re not
about collecting certain numbers of species into convenient groups. They’re not about separating groups from each other that have a certain amount of
genetic differences. It’s a relict system that holds on because it does allow scientists to communicate with each other—provided all understand the
pitfalls of using the system. But you need only sit in on one nomenclature session at a paleontology meeting to see how poorly it works for establishing
actual relationships between organisms.

]]>Your Holiday DinosaurTue, 02 Dec 2014 18:38:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/your_holiday_dinosaur
http://www.csicop.org/specialarticles/show/your_holiday_dinosaurMost vertebrate paleontologists agree that modern birds evolved from dinosaurs. To paleontologists, there is no simple bird-dinosaur dichotomy. Rather there is a continuum of animals that are at first, clearly dinosaurs (like Tyrannosaurus and Velociraptor), then at the end are clearly birds, like all the modern birds that we see. We recognize lots of ‘in between’ animals, like Archaeopteryx that appear to be at once both bird and dinosaur.

To simplify, many, including me, refer to birds as dinosaurs. Sometimes, we add the term ‘avian’ or ‘non-avian’ to the front of dinosaur, to distinguish between modern, flying birds and their relatives, and the big scary ones that went extinct 65 million years ago.

The interesting outcome is that what this means is that, at least in the United States, we traditionally have a huge family meal on the fourth Thursday of November, in which we consume vast quantities of roasted dinosaur meat.

All right, but how do we know that?

If you’re like me, you need only go outside and hang out with the chickens to realize that these are just feathered versions of the velociraptors from the original Jurassic Park movie.

Yeah, but maybe they based those off of chickens.

I can do better than that, I promise. What is presented here is a re-hashing of what is already available here, at the University of California Museum of Paleontology’s website.

They start with a simple turkey skeleton and explain some of its dinosaurian features:

The skeleton of the Wild Turkey, Meleagris gallipavo. Here is the basic skeleton. Credit: University of California Museum of Paleontology. Copyright 1994-2014 by the Regents of the University of California, all rights reserved. Used with permission.

I’ll be expanding on this using this nice summary of the similarities between birds and dinosaurs prepared by Thomas Holtz, based on the skeletal drawing above.

The skeleton of the Wild Turkey, adapted to show dinosaurian features. In black is the basic skeleton. Red arrows highlight characteristics shared between birds and dinosaurs. Credit: Skeleton from UCMP Copyright 1994-2014 by the Regents of the University of California, all rights reserved. Used with permission.; Red highlights: Thomas Holtz (@TomHoltzPaleo on Twitter)

There are a lot of terms here that might be a little overwhelming, so I’d like to summarize them first. We’ll go step by step, highlighting the evolution and relationships between birds and dinosaurs.

First, let’s consider the taxonomy – the scientific names. These are listed from most inclusive (the biggest groups) to the most specific (smaller groups – subsets of the next group up).

Archosauriformes – A subset of reptiles including crocodylians, dinosaurs, and birds.

Ornithodira – A subset of archosauriforms that are more closely related to dinosaurs and birds than to crocodylians.

Dinosauromorpha – Includes only dinosaurs and birds, and some other closely related animals.

Dinosauria – The dinosaurs (which includes birds).

Theropoda – Mostly carnivorous dinosaurs, characterized by being bipedal and having three functional digits on the feet, and a fourth digit separated from the rest of the toes

Neotheropoda – A broad group that includes all but the most primitive of theropods

Tetanuridae – A subgroup of neotheropods that are characterized by having a stiff tail.

Avetheropoda – These are more advanced theropod dinosaurs and birds. These are more bird-like.

Maniraptora – Includes long arms and three-fingered hands with some special adaptations to the wrist.

Eumaniraptora – specialized maniraptorans with an especially mobile tail. Archaeopteryx is a Eumaniraptoran.

Pygostylia – possess the specialized tail of modern birds called the pygostyle, which is short and stubby, but great for tail feathers to attach to.

Ornithothoraces – show fusion of ankle and foot bones, as well as fusion of wrist and hand bones, characteristic of birds.

Euornithes – Have a fully modern pygostyle, but still has primitive features like belly ribs (gastralia).

Carinatae – possess a keeled sternum, used in powered flight

Aves – lack teeth. These are modern birds.

We can illustrate these relationships in the following drawing. Bigger boxes are larger taxonomic divisions and include more animals. The divisions get smaller and smaller as we move toward modern birds, Aves (in darkest red).

Features of all of these groups are seen in the turkey. Let’s go through and explain them all.

Archosauroformes

Antorbital fenestra – This refers to a particular opening in the skull that lies directly in front of the eye socket. This is why it’s hard sometimes to figure out which hole is the eye-hole in a T. rex skull. Antorbital literally means ‘in front of the eye.’ Fenestra means ‘window.’

Endothermy? – This is a fancy way to say ‘warm-blooded.’ It’s possible that warm-bloodedness – the ability to generate body heat – evolved in ornithodirans.

Cervical vertebrae distinct from dorsal vertebrae – The bones of the back can be divided into several groups, the cervicals (neck), dorsals (where the ribs attach), lumbar (the lower back in humans – rib-free in other animals), sacral (where the pelvis attaches), and caudal (tail bones). Prior to this, the cervical vertebrae weren’t different than dorsal vertebrae. They all had ribs.

Alligator cervial-to-dorsal vertebrae transition. Vertebrae are very similar, only really distinct by having ribs (dorsal vertebrae only). Four cervical vertebrae to the left, five dorsal to the right.

Cervical-to-dorsal vertebrae transition in a duck. Notice the change in the shape of the vertebrae. Five complete cervical vertebrae to the left, three dorsal vertebrae to the right.

Dinosauromorpha

Parasagittal stance – This is standing with the limbs directly under the body (like humans, horses, and birds), rather than sprawled out to the side (like crocodiles and salamanders).

Hinge-like ankle joint – Because of the improved stance, the foot can now hinge nicely on the shinbone (tibia) in a forward and back motion. They were not able to rotate their ankles like we can.

Dinosauria

Obligate bipedality – This means they have no choice but to stand on two legs. Sure, they might be able to put their hands down, but they couldn’t walk on all fours any more than we can. Being on their feet is their preferred mode of transportation. Makes it easy to use the hands for other things…

Endothermy? – It’s possible that warm-bloodedness evolved with the dinosaurs and not with the ornithodirans. We haven’t sorted this out yet.

Feathers? -There’s lots of evidence for feathers on dinosaurs. We’re not sure yet if all dinosaurs had feathers, or only certain groups. At this point it looks like pretty-much all of them had feathers.

Theropoda

Loss of digit V on hand – Digit V is equivalent to your pinky finger. Theropods only have four fingers.

Neotheropoda

Furculum – This is the wishbone in your turkey. Yeah, Tyrannosaurus had one. It didn’t look quite like the one you’ll get from your turkey, but it was there. Here’s where the furculum sits in a pigeon.

Pigeon furculum, also known as the wishbone. Credit: Toony CC 3.0 By-SA

The furculum of a dinosaur looks a little different than a turkey wishbone. But it’s there!

Feathers? – Well, if feathers hadn’t evolved earlier, they almost certainly had evolved by the time the tetanurans came about.

Avetheropoda

Loss of digit IV on hand – This is the same as your ring finger. Avetheropods only have three fingers.

Maniraptoriformes

Pennaceous feathers – These are the stiff feathers that have a stalk or quill. Before this, it may have been mostly downy fuzz.

Maniraptora

Laterally-oriented shoulder joint – The shoulder joint aims to the side, like ours does, rather than pointing toward the ground like most other animals.

Backwards-pointing pubis – The pelvis is composed of three parts, the ilium, ichium, and pubis. In theropods like T. rex, the pubis points forward, but in birds this points backwards.

The pelvis of a duck, showing the backward pointing pubis and pygostyle.

Enlarged sternum – This is where ribs connect in the front of the body. It is also where big muscles like the pectoralis connect. Enlarging the sternum allows for greater size and strength of the pectoralis muscles, which are important for flapping.

Semilunate carpal – This is a specialized wrist bone which allows the wrist to bend to the side.

Eumaniraptora

Proximally-mobile caudal vertebrae – These are the tail bones. Much of the tail is stiff, but the bones closest to the body (proximal) are able to move quite a lot. In birds, this flexibility is what allows them the move their tails around and steer so well.

Distally-placed metatarsal I – Metatarsal I is the foot bone connected to the big toe. To say ‘distally-placed’ means that it is placed far from the main part of the body, more close to the foot.

Pygostylia

Has a pygostyle – A pygostyle is specialized caudal vertebrae for the connection of tail feathers. It replaces the long, stiff tail of earlier dinosaurs.

The pygostyle, where the tail feathers attach in a bird.

Ornithothoraces

Carpometacarpus – This is a fusion of wrist and hand bones characteristic of birds.

Structure of the wing bones of a modern bird. Credit: Shyamal CC 2.5 SA-By

Wing of a duck.

Tarsometatarsus – This is a fusion of ankle and foot bones also characteristic of birds.

Foot of a duck showing the fusion of the tarsus and metatarsus (what appears as a single bone above the toes)

Additional cervical vertebrae – Unlike mammals, birds and their relatives aren’t limited to only seven neck vertebrae. They have many and kept gaining more allowing them to do crazy looking things like spin their heads around nearly 360 degrees.

Backward pointing metatarsal I – One toe – the equivalent of our big toe – points backwards on the foot.

Pigeon. Metatarsal I is part of the backward pointing toe. It is very close to the other toes, rather than higher on the foot.

Euornithes

No unguals on manus – The third bone of the fingers (the one that has a nail on it) is missing.

Has a stubby pygostyle – Just like modern birds, the pygostyle is a little tiny thing.

Carinatae

Keeled sternum – Just like a yacht, the sternum in most birds has a keel sticking out from it. This provides even more surface for the pectoral muscles to attach. (This is also that delicious breast meat that we like so much.)

I invite you to discuss this over dinner this Thanksgiving or Christmas. I might do so myself. Maybe then the family will leave me alone.

]]>Can Science Support Creationism?Tue, 04 Feb 2014 12:50:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/can_science_support_creationism
http://www.csicop.org/specialarticles/show/can_science_support_creationismI gave a talk for RIT Skeptics with the above title. This post is the analogue version of the presentation for those who couldn’t attend. It’s also a good way for me to organize my thoughts in a linear fashion.

The point of the talk is to show whether or not some ideas of ‘Special Creation’ can be supported by science. Specifically, I’ll compare the Theory of Evolution with concepts of Intelligent Design and Scientific Creationism.

In a general sense, Creationism is the idea that some supernatural power is responsible for the diversity of life on Earth. This supernatural force is responsible for our existence on this planet. This is in contradiction to the scientific theory of Evolution, which holds that the diversity of life on Earth today can be tracked back to a single common, unicellular, ancestor, and that the diversity is due to the accumulation of minute changes along lineages over billions of years.

To begin, let’s talk about what constitutes ‘science.’

How the scientific method works, from observations to falsification. If a hypothesis is falsified, the hypothesis may be modified.

We’ve probably all heard at some point of the ‘scientific method.’ In short, the idea is that observations are made by the scientist.

In developing the hypothesis, the scientist also comes up with some predictions and at least one test to check whether the hypothesis is valid.

If this is true, then every time a Bumble falls down, it should bounce.

Then the scientist runs the test.

Shove the Bumble off a cliff.

The scientist awaits the results.

Oops. The Bumble didn’t bounce.

The scientist has either supported or falsified the hypothesis. If the hypothesis is falsified, then it’s not all over. The hypothesis can be revised.

Maybe it’s not the Bumble that bounces. Maybe it’s where it falls off the cliff that matters.

Then we can test the new hypothesis.

Take another Bumble to the original cliff where the first Bumble bounced and give it a shove.

And the process goes on by asking better and more focused questions. What is it about a Bumble that makes it bounce? Can other things bounce like Bumbles? What’s so special about that one cliff?

What’s crucial here is that the hypothesis (Bumbles bounce) makes predictions (Bumbles will always bounce) and is testable (shove a Bumble off a cliff) and falsifiable (if the Bumble doesn’t bounce).

In order for something to be considered scientific, it must meet these criteria.

One other thing that science does is intentionally limit its explanations to the natural, material, observable world. But we’re going to set this aside for the sake of this discussion.

Evolution is a scientific theory. It has met the above criteria and has been repeatedly tested and has not yet been disproved. Some aspects of it are not yet understood, but on the whole, Evolution is the best scientific explanation for the diversity of life on Earth.

I will mention here at once, however, that the Theory of Evolution is not a theory to explain life’s origin (it assumes that life is already present), it is not a theory to explain the origin of the universe, nor is it a theory to explain the complexity of anything.

It’s really important to define what is meant by ‘Creationism,’ because it can mean a lot of things. I’m speaking specifically here of the two types of Creationism that are most often trying to be promoted as science in the United States: Intelligent Design and Scientific Creationism. Both claim to be based in science (and indeed, look kinda science-y), and proponents of each are trying to get these ideas taught in science classrooms.

So let’s talk about these things.

INTELLIGENT DESIGN

Intelligent Design is the idea that there are things in biology that are simply too complex to have arisen by the mechanisms proposed by Evolution. For example, you can’t have a mouse trap with fewer than eight parts. All the parts must come into existence at once, or some outer intelligence has to make those things. Another common example is the idea that if you found a pocket watch on the beach, you wouldn’t assume that it just formed there. You’d assume that someone made it.

Intelligent Design puts forward that certain mechanisms (like the flagellum on bacteria or the blood clotting cascade of enzymes) is far too complex to be the result of even billions of years of evolution. The catch-phrase for this is “irreducibly complex.” These things, Intelligent Design claims, were made by an external force, and external intelligence. In most cases, this intelligence is presumed to be the God of the Judeo-Christian bible. (It is most often, in the United States anyway, Christians who argue for this.) Thus, an eight-piece mouse trap is irreducibly complex. A four-piece mousetrap won’t work.

It is interesting that Intelligent Design does support many of the basic arguments of the Theory of Evolution. Intelligent Design is fine with micro-evolution, the instances of evolution that we can observe, like the development of resistant strains of bacteria. This is fine, because in that case we’re not changing species of bacteria, just strains. The variety of dog breeds is fine too. Breeds or races of one species, though radically different in appearance, are still all one species.

SCIENTIFIC CREATIONISM

Like Intelligent Design, Scientific Creationism claims to have scientific proof that the Earth and everything on it was specially created by some supernatural force. Also, similar to Intelligent Design, it generally comes from fundamentalist Christians. In this case, the arguments go beyond an explanation for the diversity of life, but focus on the bible-literalist idea that the Earth is about 6,000 years old.

To do this, creation scientists use the same techniques the I as a geoscientist might use, but their goal is to prove that the Earth is much younger than the rest of the geoscience community thinks it is. Creation scientists in the laboratory are indistinguishable from mainstream scientists such as myself.

ARE EITHER OF THESE SCIENTIFIC?

We need to ask ourselves if these two ideas meet the criteria above for being scientific.

Let’s start with Intelligent Design.

Hypothesis – Parts of biological systems are too complex to have arisen naturally. These are irreducibly complex.

Makes Predictions -

1) Certain parts of biological systems appear all at once and abruptly in organism lineages.

2) Any part of a greater irreducibly complex feature cannot function by itself.

Testable – Find an irreducibly complex structure or mechanism. Check to see if its parts can function outside of the whole.

Falsifiable – If parts of an irreducibly complex structure do function outside of the whole, then the hypothesis is falsified and must be revised.

Does the fact that we haven’t identified a without-a-doubt irreducibly complex system in living things completely refute this aspect of Intelligent Design? Maybe not.

But let’s take a step back and think about this in practical terms. Is this a useful thing to pursue? In proving that there are irreducibly complex things then we prove the existence of the supernatural. Is that useful? Could there not be other explanations? Maybe when we find something that we all agree is irreducibly complex we can have this discussion.

In the meantime, I would point out that you can have a one-part mouse trap. A wall isn’t a very efficient mouse-trap, but it can work.

Let’s take this back to the original problem: How does Intelligent Design compare with the Theory of Evolution, in regards to the diversity of life on Earth.

For microevolution, they are in exact agreement.

Hypothesis – Organisms over generations can be markedly different from their ancestors in appearance and/or physiology. These changes occur in response to stresses (or selections), whether natural (weaker organisms do not survive to reproduce) or artificial (individual organisms are selected to breed with one another to convey desirable traits to the next generation).

Makes Predictions -

1) A population of organisms under stress will change when a selective pressure is put on them.

Testable – Place a population under stress. Select the stressor carefully, however.

Falsifiable – The organisms do not change.

For macroevolution, Intelligent Design and Evolution are quite different.

Evolution’s Hypothesis – Small, step-wise changes over great periods of time will result in the entirely of biological diversity, including the development of animals versus plants and the different, large grouping within each of these kingdoms. (And this also includes the fungi and other kingdoms of organisms on Earth.)

Prediction – In the fossil record, a continuum of organisms, including forms intermediate between large divisions of organisms may be found.

Intelligent Design’s Hypothesis – The large groups of organisms are differentiated by irreducibly complex structures and are thus completely distinct.

Predictions – No intermediate forms are possible in the fossil record.

To test either of these hypotheses, one need to dig (literally) into the fossil record.

What does the fossil record say? There are abundant transitional forms, including the transitional form between fish and amphibians. But there is yet argument (though not in the paleontological community) about whether these are truly transitional forms.

How about Scientific Creationism:

Hypothesis – The Earth is only 6000 years old, thus too short lived for biological evolution to have occurred.

Makes Predictions -

1) No geological materials may be greater than 6000 years old.

2) Catastrophic events from the bible, for example Noah’s flood, are recorded in the rock record.

Testable – The geosciences has all sorts of methods for assigning ages to rocks. The geosciences also have methods for identifying flood events in the rock record.

Falsifiable – The discovery of ages older than 6000 years negates the first prediction. The absence of evidence of a global catastrophic flood negates the second prediction.

Well, this seems as if it ought to be really easy to disprove and cast aside out-of-hand. I mean there are lots of dates of the Earth and geological materials that are a great deal older than 6000 years. But, if you’re not science-minded, you might not know that. You might take a man with his Bachelor’s degree in Geology at his word when he tells you that the rocks he dated were only 6000 years old.

It’s equally possible that a lay person might not realize that the lovely evidence for flooding that this same geologist is presenting is really limited in geographic extent, and is in no way global, like he’s claiming.

Creation Science in that regard is a little diabolical. The science that creation scientists are doing – their methods – are fine and fair. The difficulty is their extension into broad conclusions that overreach the results of their analyses. But you need to have a solid background in science to recognize that.

But how does Creation Science stack up against Evolution, with regards to the diversity of life on Earth?

Evolution’s Hypothesis – Small, step-wise changes over great periods of time will result in the entirety of biological diversity, including the development of animals versus plants and the different, large grouping within each of these kingdoms. (And this also includes the fungi and other kingdoms of organisms on Earth.)

Prediction – In the fossil record, a continuum of organisms, including forms intermediate between large divisions of organisms may be found.

Creation Sciences’s Hypothesis – The Earth is only 6000 years old. While microevolution may yet be possible, the major groups (kinds) of organisms were placed on the Earth at its formation 6000 years ago.

Predictions – The fossil record should only include fossils of modern kinds. Hypothetical ancestors could not have existed. Anything other than the modern kinds may have once existed, but did not survive the catastrophic events like Noah’s flood.

Again, to test these predictions, one need only dig into the rock record. The fossil record should be dominated by modern ‘kinds’ of animals, with animals of different kinds being buried below layers indicating some manner of catastrophic event. (It should also be impossible to find any rocks older than 6000 years).

So, are either Intelligent Design or Scientific Creationism supported by science?

The answer is no.

We can sure present them as science, complete with predictions. But their predictions fail. We do have rocks older than 6000 years old. We do have irreducibly complex structures that are reducible. We do have intermediate forms in the fossil record.

Time and again, science has refuted the predictions made by Intelligent Design and by Scientific Creationism.

And when they fail, both camps of creationism induce the supernatural itself, claiming that where Evolution does not yet have an answer, that’s where the supernatural resides, or contradictory evidence has been placed by the supernatural itself to deceive us.

Remember what I said early on? Science intentionally ignores the supernatural. It’s left out of the equation. Intelligent Design and Creation Science both fail as true science immediately, because of their purpose to prove that the supernatural exists.

Both Intelligent Design and Scientific Creationism support Evolution’s concept of microevolution, but not macroevolution (but for totally different reasons). Their predictions to support their concept of macroevolution (the presence of ‘kinds’) fail in the rock record.

Both Intelligent Design and Scientific Creationism are microevolution (a scientific concept explained by Evolution), plus some other ideas that have no scientific support. These other ideas do not agree with scientific observations. So if we’re going to stick to the science, we’d best stick to Evolution.

]]>ExpelledFri, 16 May 2008 15:01:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/expelled
http://www.csicop.org/specialarticles/show/expelledI recently attended a showing of Ben Stein’s new movie “Expelled.” I could, very easily, go off on a point-by-point rebuttal of the film, but I feel that would be a waste of energy, especially given that the National Center for Science Education has created a wonderful website that does this in a most elegant manner. Instead, I’d like to share my guttural feelings and thoughts about the movie, as a scientist, a paleontologist, and an evolutionist.

What surprised me first about my own reaction to the movie is that it really didn’t bother me that much; whereas, my friends who saw it with me were very upset about its content. Why didn’t it bother me so much? I think it was because I saw it as silly. It brought up the same old, tired arguments used again and again to ‘refute’ evolution. Additionally, the scientists and their stories that were highlighted in the film as having been ‘expelled’ for supporting intelligent design as a valid theory didn’t strike me as having been singled out for their support of ID. They simply lost their jobs as many in academia do (myself included): their contract wasn’t renewed, they didn’t get tenure, or the funding for their position simply ran out.

Then I realized that my own reaction was buffered, due in part to my constant exposure to the ‘usual’ arguments and in part to my familiarity with the workings of academia. Had I not already been familiar with the arguments in favor of ID and were I not an active member of the academic community, I would have been horrified by the implication that academic freedom was at risk and that good scientists were losing their jobs for promoting ideas that conflicted with mainstream lines of thought. What’s more, it’s possible I would have found Stein’s arguments compelling enough to believe. Once I realized this, I too was deeply upset with the film.

The movie starts out innocently enough. (Stein) is told that another scientist lost his job for supporting a viewpoint opposing that of mainstream science. The scientist who lost his job was apparently a supporter of the ‘theory’ of Intelligent Design, and this is why he lost his job. Surely this must be a unique instance, Stein [pretends to posit], but he parades several examples of proponents of ID losing their academic, scientific jobs for supporting this viewpoint. While I thought the question was fair - did these scientists lose their jobs because they supported ID? - my conclusion was quite the opposite of Stein’s.

Richard Sternberg published a paper whose authors supported ID in a mainstream science journal that he himself edited. He subsequently “lost his position". The movie fails to mention that it was never a permanent position - his contract was simply not renewed. Editorships are seldom if ever permanent, anyway.

Caroline Crocker also lost her job. Once again the movie omits an important detail - she was in a non-tenure-track position. The funding ran out or her contract was not renewed - these things happen all the time. It’s happened to me. It’s an accepted, expected part of academic life. Guillermo Gonzales didn’t survive the tenure review process. Clearly, he doesn't understand how tenure review works, and he misconstrues it in the movie. Whether or not a person gets tenure does not depend upon their colleagues at their home institution agreeing with or even liking them. During tenure review, letters are sent to persons all over the world in a person’s specialty, to find out whether or not the scientific community at large has even heard of the tenure candidate and if they think that the candidate is deserving of tenure. Nothing about these examples of ‘expelled’ scientists struck me as being peculiar or being anti-ID.

More troubling in the film were the interviews of scientists that do not support the ‘theory’ of intelligent design or even the idea of special creation. These interviews make scientists that support evolution appear to be pompous, egocentric zealots that support their ‘pet’ idea at any cost. I could tell immediately that each and every one of them had been misled about the purpose of the interview. I knew it, because they chatted about evolution and intelligent design in the same way I chat with colleagues about intelligent design when I already know we agree that ID is not valid science. That is to say, the supporters of evolution had clearly been led to believe that Ben Stein and crew were also supporters of evolution. Had they known the intent of the interview, they might not have been so flippant about their opinion of ID. Then again, maybe they would have been, and that’s at least in part why they were selected to be interviewed.

However, if those interviewed had known the purpose of the interview, they certainly would not have indulged Stein with answers to some of his questions (for example Richard Dawkins putting a number on just how certain he is that God does not exist and his discussion of how proof of design might be discovered and what it might mean). And, most importantly, they would have been more deliberate in their answers and explanations for some questions. Michael Ruse did a terrible job of explaining the origin of life ‘on the backs of crystals.’ It isn’t that the idea of minerals catalyzing early life functions is a bad hypothesis - I think it’s a good one - but that Ruse left out a number of details and grossly oversimplified his explanation, thinking that Stein supported his position, that Stein was kidding, and/or that the footage simply would not be used. Stein took this and ran with it, asserting that all scientists agree that life began with a complete cell, and making a mockery of what Ruse had just said.

When I survey my colleagues, none of them think that the first life form was a complete cell. When I ask my non-scientist friends, many of them don’t think the first life form was a complete cell either. They usually mention RNA, which is much closer to what most scientists really think than that the first life form was a perfect cell. You might be able to argue that the most primitive form of life today is a single celled bacteria - this after you argue about whether or not viruses are ‘alive.’ But life began about 3.5 billion years ago! Even the most primitive organism on the Earth today has benefited from 3.5 billion years of evolution!

What is needed is a better definition of what ‘life’ is. In the earth and biological sciences, life is carefully defined in terms of thermodynamic disequilibrium, or as self-replication of molecules. With this definition, the idea that life arose ‘on the backs of crystals,’ ceases to be so absurd. This brings us back to the question of whether or not viruses are ‘alive,’ and will likely be the topic of a forthcoming column.

One aspect of the film I found appalling was the portrayal of Eugenie Scott, Executive Director of the National Center for Science Education, as a bad person. She was put forward as if she was specifically trying to attack everyone that supports intelligent design and that she was single-handedly responsible for folks like Richard Sternberg losing their jobs. Personally, I've found Eugenie to be among the kindest human beings I've ever met. She goes to great efforts to accommodate the different viewpoints of people. She simply draws the line when science is at stake. And yet, she was presented as smug and evil.

On the flip side of this was David Berlinski, (a fellow of the Discovery Institute’s Center for Science and Culture) who was presented as a strong advocate for the position that science is under siege by the “Darwinian Establishment.” He just oozed pompousness, reclining in his chair during the interviews, frequently leaning back so far that his knee was in every shot, blocking his face. Stein introduced Berlinski as having taught at this prestigious university and that prestigious university from the U.S. to Europe as if this were a good thing. My reaction was, “why can’t this guy keep a job?” I don’t know Berlinski’s whole story; all I know is that I wasn’t impressed, and I don’t really care to search for his resume.

The single most disturbing point of the film, of course, is the portrayal that accepting evolution is somehow equivalent to thinking that the Holocaust was a good thing. The line of logic was thus: believing evolution (specifically Darwinism) leads to atheism; atheism and Darwinism leads to eugenics, the devaluing of human life, and tragic events like the Holocaust. The film even included a dishonestly edited quote from Darwin himself that seemed to suggest that Darwin would have advocated selective breeding in humans and the sterilization of the “feeble minded.” Other quotes by Darwin were left out, including one that says that even though we might selectively breed dogs or farm animals, such is not proper for humans:

"With highly civilized nations continued progress depends in a subordinate degree on natural selection; for such nations do not supplant and exterminate one another as do savage tribes.” Darwin, The Descent of Man (2nd Ed), Chapter 5, 1874

The main theme of the film is that freedom of inquiry in science is being repressed, and that there is only academic freedom for those in agreement with the “Darwinian Establishment.” I suppose I could understand why the Theory of Evolution is such a threat, if I were heavily religious and looked to the bible (or other holy text) for answers to the big questions like why am I here, how did I get here, and where am I going. The trouble is that these ‘scientific’ ideas that are being repressed - “expelled” if you will - aren’t scientific ideas at all. Ideally, science doesn't start with the conclusion and then try to find evidence to support that conclusion. Science goes where it goes, whether we like the answer to our original question or not.

In an earlier column of mine, I explored the differences between ID and evolutionary theory. I concluded that ID isn’t scientific at all. In fact, it advocates stopping a line of scientific inquiry when the results begin to challenge our ideas about how things should be, because surely this must be the fingerprint of God. Is this what we want to teach our children? To stop asking questions when the answers make us feel uncomfortable? I don’t think so.

]]>On Creation ScienceWed, 26 Sep 2007 15:17:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/on_creation_science
http://www.csicop.org/specialarticles/show/on_creation_scienceIt is best to fully understand the point of view of those with whom you disagree before you engage them in productive discussion about that topic. In the real world, however, this is seldom practical. Most of us simply don’t have the time or energy to devote to studying things that do not have an important and immediate affect on the daily goings-on of our lives. This is why we typically defer to authoritative experts or elected officials about matters that we simply can’t devote attention to.

In the case of the debate between the validity of the Theory of Evolution versus the truth of Creation Science (in all its forms), the arguments often require an advanced knowledge of geology, biology, mathematics, physics, and chemistry — not to mention an understanding of what really is written in Scripture. Proponents on either side of the argument struggle with the scope of the debate, and often rely on the testimony of experts about specific aspects of the debate. Even then, the scope of the argument is so voluminous that even the experts seldom fully understand the perspective of the counter argument. Many in the paleontological community (who almost all accept the Theory of Evolution as the best explanation for the diversity of life on our planet) agree that it would be ideal to understand the ‘scientific’ arguments of Creationists, but few are free to devote the resources necessary to understand the various Creationist viewpoints.

Recently, I had the opportunity to attend a full-day “Creation Science Seminar,” presented by a geologist from the Institute of Creation Research (ICR). ICR promotes a more literal translation of Genesis from the Bible, in which the Earth is only about 6000 years old and was created, along with all plants and animals, in six days. This is termed Young Earth Creationism (YEC) and geologist William Hoesch presented the scientific evidence supporting it.

The following week I attended a panel debate called “A Skeptics Forum.” This was promoted by an organization called Reasons to Believe that supports the ‘Theory’ of Intelligent Design (ID) and a less literal interpretation of Genesis.

Perhaps the most striking observation that I can make, having attended these two events, is that the two competing creationist theories disagree with each other as much as they oppose the Theory of Evolution. What I found to be more disturbing was that the scientific evidence for a 6000-year-old Earth was more credible than that for Intelligent Design. I find that ID is easy to show to be a pseudo-science. Creation science, at least at first glance, appears to have a sound basis in the rest of secular science.

In this column, I’ll share my observations about the Creation Science Seminar and the scientific evidence for a young Earth. It’s tempting to simply write a bulleted list and refute all that was said, point by point. Instead, I’ll talk a bit about the material that was presented and the WAY in which it was presented.

My first observation, as I walked in to the seminar ‘fashionably late,’ was that the room was packed with people (more than 300!) and that William Hoesch is a very charismatic person. He has the air of a professional geologist, complete with requisite vocabulary, attire, and presentation style. I really enjoyed his presentation. The lunch buffet was excellent. And the folks I shared my table with were pleasant — though I didn’t have much to say.

The Seminar was divided into four sessions. The first session discussed six ‘trade secrets,’ presumably of secular science. These were the typical arguments against evolution, most of which were wrong or irrelevant.

That no credible mechanism for MACROevolution exists.

Macroevolution is the appearance of new taxonomic groups of organisms above the level of species. Generally, this is in reference to new classes or phyla of animals. Microevolution is the appearance of new species. Creationists seldom argue about the reality of microevolution. I would argue (as others have) that macroevolution is an extension of microevolution. There are well-understood mechanisms for microevolution; these mechanisms also apply to macroevolution. Here it is argued that macroevolution requires its own, distinct mechanism. I feel another web column coming on stay posted!

That the fossil record has not yielded any missing links.

See my last column about Tiktaalik, the ‘fish-ibian’

That the age of the earth is NOT proven to be 4.5 billion years old.

Maybe not PROVEN, but much of the evidence that we have supports that conclusion. That’s the way science works. This is the first point in the seminar that he suggests that making interpretations or inferences is no better than using your imagination. He referred to interpreting the age of rocks using the relationships between different rock units and structures in the rock or by geochemical means is merely “rank guesswork,” To me, this suggested a very poor understanding of global stratigraphy on his part, which I found discouraging. Later in the seminar, in the fourth session, Hoesch presented interesting evidence for a much younger Earth.

That machines go from order to disorder.

This one we’ve all heard before: the classic 2nd Law of Thermodynamics argument. Hoesch makes the claim that the 2nd Law applies in both open and closed systems. This left me scratching my head with a big, ‘huh’? I assume that Hoesch has had physics and understands how this stance doesn’t make a lot of sense. So, I did a little more research and have discovered (I think) how this claim is made by Creation Scientists.

The 2nd Law, in a nutshell, states that in nature, order goes to disorder. The complex becomes more simple. The required conditions for complexity to increase (the opposite of the 2nd Law) is that 1) the system must be open and 2) there must be an influx of energy into the system. Henry Morris (Morris and Parker, 1997) describes two more necessary requirements for an increase of complexity (or a decrease in entropy): 3) a program to direct the growth in complexity and 4) a mechanism for storing and converting incoming energy (Morris and Parker, 1997, Fig. 41, p. 211).

These additional conditions make Creation Science sound a little like Intelligent Design.

That the founding fathers of nearly every discipline of science were bible-believing creationists.

This is irrelevant

That coded information never happens by chance.

Just as a person has to write computer code, the code of DNA had to be written by some intelligent agent. This is another argument that smacks of Intelligent Design.

Uniformitarianism is a term that often turns up early on in introductory geology textbooks. Charles Lyell put forward the idea in his Principles of Geology, (published 1830—1833), in which he states that geological processes in the past were of the same kind and intensity as those currently observable. The opposite of this is Catastrophism, which suggests that most of Earth’s history was spent in a relatively calm, static state, punctuated by large, global-scale events — catastrophes — such as a world-wide flood.

The second and third sessions of the Creation Science Seminar set about to disprove Uniformitarianism as a valid model for past geological processes. Hoesch asserted that geologists ‘cling’ to Uniformitarianism as a unifying concept in geology, and don’t consider catastrophic events as a possibility.

This, of course, is not the slightest bit true. Geologists recognize catastrophic events in Earth’s history and make no effort to disguise the fact that such catastrophes happen. I recall distinctly a lengthy discussion about the paradigmatic shift in geology from Catastrophist (pre-Lyell), to Uniformitarian, to the modern mixture of the two (see Berggren and Van Couvering, 1984, Catastrophes and Earth History: The New Uniformitarianism).

Hoesch described a few of the basic assumptions of geology, presumably of Uniformitarian origin, and proposed a means to show that these ideas to be incorrect, using study of the effects of the eruption of Mount Saint Helens.

Idea 1) Thick rock sections take great lengths of time to form.

Idea 2) Large valleys are cut by small streams over great lengths of time.

In one day (or at most a few days), tens of feet of sediment was laid down, and then eroded to form broad valleys by large flows coming off of the mountain. Later, the broad valleys remain with only tiny streams flowing through them. According to Hoesch, if outcrops such as these were found by a geologist, the geologist would assume that the thick rock layers took millions of years to be deposited and that the little stream eroded the big valley slowly over great spans of time. So the Grand Canyon could have been formed rapidly by recession of global flood waters, rather than over millions of years by the (relatively) tiny Colorado River.

I immediately started thinking about some of the problems with this idea. The challenge of scale — the difference between 600 feet and 6000 feet — can be set aside for the sake of argument. The deposits around Mt. St. Helens were all unconsolidated to fused volcaniclastics (sedimentary materials directly from and eruption of a volcano, for example ash and pumice), whereas deposits in the Grand Canyon were limestones, sandstones, and shales overlying metamorphic and igneous rocks. This sets my geologist senses tingling — I just can’t imagine that 600 feet of fresh volcaniclastics are as difficult to erode as are 600 feet of limestone. What about the unconformities and paleosols that have been documented in the Grand Canyon? How does the lateral extent of the sediments at Mt. St. Helens compare with the lateral extent of sediments outcropping in the Grand Canyon? And fossils? Are there any fossils in the recent volcaniclastics of Mt. St. Helens? What about well-developed soils? There are soils in the strata of the Grand Canyon.

I realized that Hoesch was citing the scientific work of another person, Dr. Steve Austin. Surely, then, Hoesch was just leaving out important details for the sake of brevity and because of their technical character. I looked up Steve Austin’s original paper, published in Origins in 1984. Steve Austin has a Ph.D. in Geology from a good, secular, school. I decided I would give it a critical read just as I do for all the technical papers I read or review. I set aside a couple of hours to read it — technical papers always take me at least that long to get through and at nine pages I thought two hours would get through the paper at least once.

Imagine my disappointment when the paper only took me about 20 minutes to read. It was well written, to be sure, but presented no original science. It was a review of the mainstream technical literature with all the units converted to feet (instead of meters). There was no strong evidence that Mount Saint Helens would be a good model for a flood origin of the Grand Canyon. Dr. Austin simply states:

“What conventional geomorphic theory says takes thousands of years may, instead, be accomplished within a few years. Geomorphologists have learned that the time scale they have been trained to attach to landform development may be misleading.”

To which I respond, “yeah, so?” This was not a scholarly scientific paper; it was more like a term paper that I would expect from advanced undergraduate students, with some interesting conclusions. Had Dr. Austin addressed any of my points of query (sediment type, cementation, lateral extent, fossils, or soils) there may have been something of mainstream interest, but there wasn’t.

I was disappointed, but not yet convinced that no further research since this original paper from 1984 had been published. It’s not so unusual that the first paper that is published about a topic is kind of, well, vague. Later papers, which cite the first, usually go into greater detail. So I checked GeoRef, a literature database maintained by the American Geological Institute, which is the most comprehensive list of geoscience publications available. I figured the Origins paper might not be listed, as Origins is a small journal and probably is not indexed by GeoRef. To my surprise (and satisfaction) the Origins paper WAS listed in GeoRef, as are both his M.S. Thesis and his Ph.D. Dissertation. I did not find any more recent papers written by Dr. Austin, just a hand full of abstracts which are nice but by themselves are meaningless in mainstream geology. Then I went to the Science Citation Index, another powerful database that is not so geology-centric. I checked to see what papers may have cited the Origins paper in their own bibliography. Alas, I found no reference to the Origins paper in any subsequent scholarly work, nor did I find reference to any of Dr. Austin’s abstracts. I was not going to find the further data that I would like to see. My conclusions: It may well be true that geomorphologists have been wrong all along about the length of time needed to form a great valley, but the evidence from examination of the volcaniclastic deposits at Mt. St. Helens (specifically Austin, 1984) does not show that the basic principles of geologic time and processes are incorrect.

Hoesch set about in his next sessions to show that fossil assemblages, too, are not the result of the fortuitous preservation of the occasional dead organism, but that are of catastrophic origin. My interest was piqued immediately, since I am a genuine card-carrying (if there were a card) paleontologist. He described one fossil assemblage that I knew very little about and another that I was already familiar with.

The first assemblage was the Whitmore Nautiloid Bed of the Redwall Limestone which crops out in the Grand Canyon, a bed in which are preserved multitudes of unbroken shells of an extinct group of animals called ammonites. Ammonites and nautiloids can be thought of as very similar looking to the modern chambered nautilus — kind of a squid in a shell. In the case of the Whitmore Bed, the nautiloid shells were all straight, not coiled like the modern nautilus. Hoesch makes several claims related to the occurrence of nautiloids in this bed.

That there is about one specimen per square meter within the bed

That this bed extends all over the southwest, thus there are billions of nautiloids

That there is a distinct preferred orientation of shells

That the entire population is represented because the distribution of shell length plots in a lognormal distribution

That there are ‘water escape pipes,’ showing that the sediment was laid in a very short period of time in an aquatic environment

That this represented an underwater avalanche, much like the pyroclastic flows at Mt. St. Helens.

These ideas are published in the book Grand Canyon: A Different View (2003, edited by Tom Vail), in which a chapter written by Dr. Steven Austin. Dr. Wilfred Elders (2003) reviewed this book (http://home.austarnet.com.au/stear/bibliolatry_revisited_elders.htm) and made a series of points that ought to be addressed by Dr. Austin before the catastrophic death of the nautiloids in the Whitmore Bed can be taken as a serious hypothesis. I add some of my own thoughts here as well:

Is it possible this is an exaggeration (see Elders, 2003)? Where specifically were you sampling nautiloids?

Could this also be an exaggeration (see Elders, 2003)? What is the real extent of the Whitmore Bed?

How many shells were measured, from how many localities?

How does lognormal distribution equal ‘the whole population died at once’? In mammals, for example, the size or age distribution might not plot on a normal curve.

How can you prove the water escape pipes aren’t actually fossil burrows (see Elders, 2003)? (I add here that Hoesch proclaimed while describing this bit of evidence that “this is actually credible!”)

I’ll be getting my copy of Grand Canyon: A Different View soon. I’ll be interested to read this chapter first-hand. Another book I will be getting soon is Grand Canyon: Monument to Catastrophe published in 1994 and edited by Dr. Austin.

Hoesch’s second example of a catastrophic formation of a fossil bed comes from the Brushy Basin Member of the Morrison Formation in Dinosaur National Monument. For this, I don’t know what to say

It is, actually, generally accepted that the fossil bed on display at Dinosaur National Monument represents the sudden death of a large group of animals, likely due to a sudden flood. These things happen, even today. But the sudden death of hundreds or even thousands of animals during a flood today does not imply a global catastrophic flood.

Many localities in the Morrison Formation are similar in appearance and origin — a tangled knot of bones that represents the mass death of animals due to a flood. Hoesch cited 20 localities in the Morrison. Add to that the one (or more?) from the Whitmore Bed and that makes 21 localities that show what Hoesch called a watery catastrophe, wherein the victims were all transported some unknown distance, and that death occurred in unheard of scales.

n the end, I feel that the arguments made for catastrophic extinction of animals from the singular global Flood are pretty weak. What about all the other thousands of fossil localities out there? What about the continuous successions of unicellular microorganisms in marine rocks? What about isolated fossil remains, when it’s just one or two individuals found together? How do you explain the 136 fossil localities that I found in my doctoral research field area, that span about 2000 feet of section, clearly lie in ancient stream channels, and lie next to some very lovely ancient soils?

The final session of the day was the ‘big one’ in which Hoesch planned to show, once and for all, that the Earth was merely thousands of years old, not billions. His three lines of evidence are:

The presence of excess helium in zircons found in rocks otherwise considered billions of years old

The pattern of polonium radiohalos in biotite, in the absence of radiohalos of other elements

The presence of Carbon-14 in rocks considered too old for carbon dating methods

This was by far the most technical part of the seminar, which included some research that has, in fact, been published in the mainstream scientific literature. It is with this that I can now fully understand what distinguishes Science from Creation Science.

In mainstream science, it is not so unusual to publish results, even when they are in direct conflict with ‘conventional’ knowledge. Yes, scientists ARE interested to know that there is far more helium in zircons than we might expect. Yes, it is curious that it seems that Polonium isotopes underwent radioactive decay separated from their parent isotopes. Yes, scientists ARE interested to know about fossils, otherwise dated at millions of years old, that have carbon-14 in sufficient quantities to perform carbon-dating.

The difference between Science and Creation Science is the way in which these results are interpreted. Science says, “Gee, that’s curious. How could that be? This could imply that the Earth is young, but that conclusion is not supported by other lines of evidence. Let’s write a grant proposal and do some more work.” Creation Science says, “See! It’s not how you thought! You were misled! Let’s write this up as irrefutable proof that the Earth is young! And if the Earth is young, well then it must have been created!”

The empirical data that Creation Scientists collect are generally sound. But their data sets are small and the conclusions drawn overreach what other Scientists would consider reasonable. On first glance, the conclusion of a young Earth seems sound, but on closer inspection, including reading of the primary scientific-creationist literature, some important points are not addressed, glossed over, or worse: misunderstood. Would that I were able to review these papers before they went into publication! Of course, this is the very reason why these papers are not published in mainstream scientific literature. It’s not that the conclusion of divine creation 6000 years ago is too radical for the data set; it’s that the scientific basis of the work is not very well argued. It’s so poorly argued in fact, that I have a hard time taking it seriously. For example, in the seminal paper (Humphreys et al., 2003) discussing the diffusion of helium from zircons:

Humphreys et al (2003) more than once make excuses for the insufficiency of their research. In reference to a paper that had been published in Geophysical Research Letters: “The theory is very complex, and no creationist expert in the field has yet reviewed it to see whether it is well founded.” Later when discussing the imperfection of their model: “But accounting for anisotropy in the biotite [that biotite crystals split on a single plane] would be quite difficult, so we leave that refinement to the next generation of analysts.”

Humphreys et al (2003) also do not explain adequately their concept of ‘closure’ to Helium in zircons. Had I reviewed the paper I would have asked them to elaborate on it a lot more.

Humprheys et al (2003) summarized its conclusions into one line: “Helium diffusion casts doubt on uniformitarian long-age interpretations of nuclear data [I’m ok with this] and strongly supports the young world of Scripture [Gasp! Your bias is showing!]”

The above points, coupled with considerable uniformitarian-bashing and the occasional quote from scripture, really leaves me disappointed in the LACK of professional science being presented in the paper.

Hoesch repeatedly made comments like: “your interpretation is only as good as your assumptions.” Well, he and his colleagues make one BIG assumption that the rest of us in secular science don’t make: that there is a supernatural power (God, if you will) that made things as they now are. In the end, it is obvious to me that this is the one thing that distinguishes creation scientists (YECs or advocates of Intelligent Design) from other mainstream scientists. This bias causes creation scientists to hesitate before studying other ideas or models that may contradict the results that they have already gotten. Their goal is merely to show that secular science may be wrong. If secular science could be wrong, creation scientists are satisfied that God could have created the universe, and there is no longer the urgent need to refine or improve their models.

This is reflected in the utter lack of professional, peer-reviewed papers that have been published by creation scientists. Most of what has been published on these various topics was written in the 1980’s, published in creation science (not mainstream science) journals, and/or was nothing more than an abstract for a poster presented at a professional meeting. The last two types of publication do not constitute serious, widely accepted science. The first point that most of the ‘seminal’ papers were written in the 1980’s while there has been very little since, prompts the following questions:

Why aren’t there more recent publications?

What have these scientists been doing in the meantime?

This kind of research effort is considered weak at best by mainstream science and it defies logic that creation scientists consider their work ‘robust.’

For fun, I plan to read and review (as I would any technical paper), several of the creation science papers noted in this column as well as others I have come across as I prepared this column. Perhaps if the lay public and the creation scientists themselves saw a critical scientific review of their work, they would either step back from calling their brand of research science or would step up their research efforts so that they were actually doing bona fide science. We’ll see.

]]>Use and Abuse of the Fossil Record: The Case of the &lsquo;Fish-ibian&rsquo;Wed, 13 Sep 2006 14:47:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/use_and_abuse_of_the_fossil_record_the_case_of_the_fish-ibian
http://www.csicop.org/specialarticles/show/use_and_abuse_of_the_fossil_record_the_case_of_the_fish-ibianA common argument of creationism is that no transitional forms between major organismal groups (e.g. the classes of the vertebrates: fish, birds, mammals etc.) are seen in the fossil record. However, paleontologists have uncovered a great wealth of fossils that are clearly transitional forms. In this essay, I will specifically address the transition from aquatic fish to terrestrial amphibian. First, let’s review what a ‘transitional’ form is and how we might recognize it.

A simple phylogeny for vertebrates.

Above is a simple phylogeny for vertebrates. All vertebrates are united by having a spinal column. The red lines are the evolutionary relationships among various groups of vertebrates. As one moves upward along any of these evolutionary lines, one moves forward in time, toward more ‘modern’ or ‘advanced’ species (see my discussion of the term ‘advanced’ in my previous column here). The splits between groups occurred among ‘primitive’ members of the groups. For example, the first amphibians lie on the phylogeny at the point labeled “2” which represents the origin of terrestrial locomotion. These first amphibians, while classified as amphibians, are quite different from modern frogs and salamanders we see today. These first amphibians evolved from primitive fishes, which are also unlike any fish we have today.

Positions on the phylogeny where transitional forms are likely to occur.

Shown above are the positions on the phylogeny where the intermediate forms between the major classes would reside. Note that these are not at the tips of the evolutionary lines (modern forms) but lower on the phylogeny. In other words, evolution moves in the direction of the blue arrows (see below) and not the red arrows.

A cartoon phylogram illustrating how evolution progresses. Red arrows show the direction of evolution were transitions between groups to have occurred between modern members of the groups. Blue arrows show how evolution proceeds where transitions between modern groups occurred in the remote past.

The transition from fishes to amphibians

Is (or was) there such a thing as a “fish-ibian?” (The term ‘fishibian’ is borrowed from Huse, 1993, p. 60.) If so, what would it look like? How would you know the “fish-ibian” was neither a fish nor an amphibian or that it was both? If we were to look at the most familiar modern fish and amphibians, we might envision the transitional form to be half frog, half trout:

A cartoon concept of a fish-amphibian intermediate form, based upon modern fish and amphibians. Though obviously silly, such “intermediates” are frequently illustrated in Christian ‘science’ textbooks.

This is the result of following the red arrows. But the reality is that the transition did not occur between modern fish and amphibians, but rather between some very ancient vertebrates some 375 million years ago. Back then, the distinction between fish and amphibians was not as immediately clear as it is today.

Cartoon of fossil genera representing the transition from fish to amphibians, which occurred in the Devonian. Tiktaalik is a new genus recently described and fits the temporal and morphological gap between known Devonian fishes and Devonian amphibians.

To put this on a phylogram, it would might something like this:

A sketch of how modern fish and amphibians, and Devonian fish and amphibians lie on a phylogram

Recently, a new fossil touted as a transitional form was discovered and described from Ellesmere Island in Canada’s Northwest Territories. This new species is called Tiktaalik rosae (Daeschler et al., 2006; Shubin et al., 2006). To understand fully the status of Tiktaalik as a transitional form between fish and amphibians, we need first to consider what it is that defines a ‘fish’ and what defines an ‘amphibian,’ and whether or not there distinctions will be visible in the fossil record.

Terms

The previous installment of this column discussed various terms used, misused, and abused in the discussion of transitional fossils. For this discussion, it will be helpful to have the following terms and definitions at our disposal.

- Taxon (taxa): A group of organisms categorized together. E.g.: “Primates” is a taxon that includes humans, apes, and monkeys. The Order “Perrisodactyla” includes several taxa of hooved mammals.

- Definition: A summary of characteristics that describes a taxon. This is generally a looser description, where some characteristics may or may not be present in all members of the taxon. Often the definition of a taxon provides ranges of variation within or among taxa or individuals within the taxon.

What is a “Fish?”

Definition: In the simplest sense, a fish is an aquatic vertebrate that depends upon water as its primary environment for day-to-day living and reproduction. Fishes breathe oxygen dissolved in water through gills. Fish have limbs adapted as fins for swimming, with no ‘fingers’ or ‘toes.’ Fishes typically have bony scales covering their entire body.

What is an “Amphibian?”

Definition: Amphibians are semi-aquatic vertebrates which divide their time between water and land for day-to-day living. Amphibians are dependent upon water for reproduction. Amphibians typically have paired limbs (arms and legs) that include ‘fingers’ and ‘toes’ for moving about on land. Amphibians also have strengthened pectoral and pelvic girdles adapted for walking on land. Amphibians begin life in water breathing through gills and later in life transition to being able to breathe air through lungs. Amphibians typically do not have bony scales on their bodies.

Amphibians first breathe with gills, and then they breathe with lungs. They go through metamorphosis.

Amphibians lay eggs.

Amphibians have smooth, moist skin.

Which Distinctive Characteristics Will Fossilize?

These definitions depend a great deal on processes, behaviors and features that would not fossilize. As paleontologists, what are we left with? What is readily evident in the fossil record? And which of these characteristics allow us to distinguish between Fishes and Amphibians?

Fish have backbones.

Amphibians have backbones.

Same

Fish are cold-blooded.

Amphibians are cold-blooded.

Same

Fish breathe with gills.

Amphibians first breathe with gills, and then with lungs.

Different in adults

Fish lay eggs in water.

Amphibians lay eggs in water.

Same

Fish have scales.

Amphibians have smooth, moist skin.

Different

Fish have fins.

Amphibians have legs and feet for walking on land.

Different

Based upon this, we see that the primary distinctions that may be made between fish and amphibians are with the breathing apparatus and skull (in adults especially), in the structure of the skin and scales, and in the structure of the limbs.

The Fish-ibian

Based upon the above characters, what would we predict the ‘fish-ibian’ to look like?

Fish-ibians had backbones.

Fish-ibians were cold-blooded.

Fish-ibians breathed with gills, but may have used lungs in adults.

Fish-ibians layed eggs in water.

Fish-ibians may or may not have had scales.

Fish-ibians had limbs adapted in part for swimming and in part for moving about on land.

The Breathing Apparatus and the Structure of the Skull

In the Devonian, the general pattern of change from fish to amphibian was the loss of the gill cover (opercular bones) and reduction in size of the postparietal bones. The loss of the opercular bones makes sense when you consider the change from breathing through gills to breathing with lungs. It also turns out that many of the bones that formerly made up the gill cover were incorporated into the shoulder apparatus of terrestrial vertebrates.

The reduction of the gill cover bones provides the animal the flexibility to lift its head and look up without having to change the orientation of the entire body, which is a tremendous advantage when the body is lying on solid land rather than floating in water.

It is important to note that modern fishes also have a great reduction in the postparietal bones when compared to fossil fishes. This is not a good distinguishing character between modern fishes and amphibians.

Simplified drawings of the skulls of some modern fish and amphibians and the skulls of Devonian fish and amphibians highlighting important changes associated with the transition from life in water to life on land

The Structure of Skin and Scales

Modern amphibians lack scales. They utilize their smooth, moist skin as a respiratory organ. Since scales are oftentimes lost or displaced in fossils, this is a difficult characteristic to address with fossils alone. We can state merely that scales may or may not have been present in the earliest amphibians and would not be surprizing in a transitional form between fish and amphibians.

Limb Structure

Perhaps one of the most striking differences between fishes and amphibians — at least in the Devonian — was in the structure of the limbs. This makes sense because a fin used to paddle a neutrally-buoyant fish about in water is not capable of lifting and hauling this same fish about on dry land.

Simplified drawings of the forelimbs of some modern fish and amphibians and the forelimbs of Devonian fish and amphibians highlighting important changes associated with the transition from life in water to life on land

One character that makes a fish a FISH is the presence of fin rays or lepidotrichia. These are the tiny bones that support the flexible, almost clothlike, membrane of the fin itself. The lepidotrichia are movable, allowing the fish to alter the shape of the fin in behavioral displays or in locomotion. Lepidotrichia are “dermal bones,” meaning that they develop embryologically directly from the dermal layers of skin. Land-dwelling vertebrates lack lepidotrichia, as the fin membrane is lost, to be replaced with bony fingers. Finger bones, as well as all wrist and arm bones, are termed “endochondral bones,” which are bones that develop from a cartilage precursor. Thus, lepidotrichia and phalanges arise from different embryological origins, despite occupying a similar position on the limb.

What is Tiktaalik?

The skull of Tiktaalik resembles that of other Devonian vertebrates, whether considered fish or amphibian. It notably lacks the bony opercular bones that characterize Devonian fishes like Eusthenopteron and Panderichthyes, and resembles more closely Devonian vertebrates regarded as amphibians such as Acanthostega and Ichthyostega. In the absence of other information, it may be best to classify Tiktaalik as an ‘amphibian.’

Tiktaalik is known to possess scales on the outer surface of its body. Based upon this, it may be most appropriate to classify Tiktaalik as a ‘fish.’

Because Tiktaalik possesses lepidotrichia, it is best classified as a ‘fish.’ However, its limb structure includes several endochondral bones (basically all but the phalanges), that are typical only of terrestrial vertebrates.

Based upon these characteristics, the authors describing Tiktaalik (Daeschler et al., 2006) classified it as a ‘fish.’

The Diagnosis of Tiktaalik — Cladistics style.

What I have presented above is only the simplest picture of distinguishing between fish and amphibians. Below is a more detailed listing of the various characteristics used to distinguish Tiktaalik from other fish and amphibians (Data from Daeschler et al., 2006; Shubin et al., 2006). Based upon this, Tiktaalik appears to be more amphibian-like than fish-like.

Click for a full sized version of this table.

So then, what is Tiktaalik?

Let’s return to the definitions of ‘fish’ and ‘amphibians’ and the characteristics of each that can fossilize.

Breathing: Fish have gills — therefore they also have the opercular bones. Amphibians (adults anyway) lack opercular bones. Tiktalik also lacks opercular bones, therefore it is more like an AMPHIBIAN.

Scales: Fish have scales covering their bodies. Modern amphibians lack scales. Tiktaalik has scales along its back, making it more like a FISH. However, it is not certain that early amphibians lacked scales, and the presence or absence of scales is not considered definitive.

Limb structure: Fish have fins with lepidotrichia used for swimming. The most ‘primitive’ fish lack the limb bones characteristic of terrestrial vertebrates. However, some lobe-finned fishes have characteristic limb bones like (in the arm) the humerus, radius, and ulna, as well as some of the carpal bones. The finger bones (metacarpals and phalanges) are lacking in lobe-finned fish, which instead have lepidotrichia. Amphibians have the complete suite of limb bones required for terrestrial locomotion (humeri to phalanges), and no lepidotrichia. Tiktaalik has lepidotrichia, which is more like a FISH. However, it also has elaborations of the bones in the limb which may have been precursors of metacarpals and phalanges, making it more like an AMPHIBIAN.

It appears that Tiktaalik is both FISH and AMPHIBIAN. It is a transitional form between fish and amphibians.

How do we classify Tiktaalik?

This is the difficult part, and where it is important to remember the distinction between taxonomy (the classification system for organisms) and phylogeny (the actual relationships among organisms). The authors that described Tiktaalik (Daeschler et al., 2006) chose to classify it as a tetrapod-like FISH. This decision was made for many reasons, mostly due to tiny details in the structure of the skull and the limbs. The cumulative result of all these small details is that Tiktaalik clearly is NOT a terrestrial vertebrate. Amphibians ARE terrestrial vertebrates. It is clear from Tiktaalik’s body form and from the rocks that it came from that it likely spent most of its life in water — like FISH. So, it is classified as such.

]]>Use and Abuse of the Fossil Record: Defining TermsSat, 09 Sep 2006 17:07:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/use_and_abuse_of_the_fossil_record_defining_terms
http://www.csicop.org/specialarticles/show/use_and_abuse_of_the_fossil_record_defining_termsA common argument of creationism is that no transitional forms between major organismal groups (e.g. the classes of the vertebrates: fish, birds, mammals etc.) are seen in the fossil record. Evolution posits that such intermediates do exist, but may not be recognized as such. In the end, it often boils down to an argument of semantics.

Science prides itself in its open framework. Science is considered to be at its best when authors freely disclose any and all assumptions that were made in their research and also present all the raw data before giving their own interpretation of it. This way, as new understandings arise and assumptions are shown to be invalid, scientists coming later can re-interpret the raw data in this new light. While laying out all the information that goes into a conclusion leaves the first scientist open to be disproved, it is GOOD science nevertheless.

In the spirit of this open framework, I wish to explain here some basic principles of biology and paleontology that, if improperly understood, can strongly affect the answer to the question: Are transitional forms found in the fossil record?

The biological species concept

A biological species (biospecies) is a population of organisms that, if left alone in their natural environment, are capable of. and DO reproduce to produce viable FERTILE offspring. So while horses and donkeys are capable of mating and producing offspring, they would not do so naturally, and their offspring (the mule) is almost never fertile. It is a similar story with lions and tigers. Which ligers and tigons do exist, the two species (lions and tigers) would never interact in the wild. This is the common definition of species used in modern biology and by all those who toss about the term ‘species’ loosely.

The morphological species concept

When all you’ve got to look at are fossils, it is not possible to tell whether two populations interbred, or if the offspring were fertile. All we have, generally, are the bones to look at. In paleontology, the term species is used to describe a population of organisms, which are distinguishable by their shape and structure from all other populations. If it looks sufficiently different, then it’s a new species.

This morphological species concept is really the only option for paleontologists. The trouble is, and this is no secret, that sometimes what in reality is one biological species may be comprised of many morphological species. In the case of mammals, a fossil morphological species (or morphospecies) may be defined based upon one or two teeth in, say, the upper jaw. A lower jaw may later be found by some other worker in some other quarry and defined itself as a new morphospecies. Only later, through careful review, might a third worker find that the two morphospecies are really only one species.

Similar problems have also arisen where there is strong sexual dimorphism in a single biological species. It is not uncommon in nature for males of a biological species to be physically quite different from females, and unless complete skeletons are found, the two sexes of one biospecies may be defined as two different morphospecies. Additionally, ontogenetic changes can cause adults of a biospecies to be distinct morphologically from the young of the same biospecies, resulting again in more than one morphospecies comprising a biospecies.

Taxonomic nomenclature

Perhaps one of the most difficult concepts to get across is the fundamental understanding that, even though our scientific naming scheme used globally for organisms (binomial nomenclature) superficially is divided along “evolutionary” lines, the naming scheme itself is truly arbitrary. The only level of nomenclature that has any physical meaning is that of “species” as discussed above. All other levels, from Kingdom to Genus, are entirely human constructs, used for convenience of discussion. In the stricter sense, many of the larger groupings (Kingdom, Phylum, Class) really apply best only to modern organisms.

Taxonomic classification of the domestic dog:

Furthermore, there are organisms in the fossil record that do not fit well into the modern taxonomic scheme. But, because we use this scheme, we essentially must force them to fit the mold. A transitional species between two classes is difficult to classify as it frequently could equally be placed into either class, or perhaps belongs in a third, now extinct class. But once classified in one class or another, it appears to cease to be transitional.

For example, we can consider the transition species from Reptilia to Aves to be called a “repti-bird.” It is at one time a ‘bird’ and a ‘reptile’ but also neither a ‘bird’ nor a ‘reptile.’ The most often cited example of the “repti-bird” is the much-maligned Archaeopteryx. It is arguably a bird, equally arguably a reptile, or potentially not really either, but instead a dinosaur. (I hasten to add here that paleontology has since discovered many more species of “repti-birds” which document the transition from dinosaur to bird far better than poor Archaeopteryx. In paleontology, Archaeopteryx is very seldom if ever touted as a direct transitional species between reptiles and birds, and is more often considered a very early bird.)

Once Archaeopteryx was ‘officially’ classified as a bird, its status as a transitional species was cast to doubt. If it’s a bird, creationism says, how can it be a transitional species leading to birds? Classification schemes are arbitrary! We use them as a matter of convenience. The classification scheme was never intended to directly imply something about phylogenetic (or evolutionary) relationships.

Primitive versus Advanced

The terms “primitive” or “advanced” must be used with caution, yet they are frequently used freely ignoring the potential confusion that could result. These terms suggest some amount of “improvement” for animals considered advanced over those considered primitive. What is really meant by “primitive” is that an animal is more similar to the original forms from which they evolved. A modern fish is equally evolved as a modern bird. We know that birds evolved from animals which were fish. However, that ancestral fish is long extinct. That same ancestral fish may have been the ancestor of modern fishes as well. So when we call a fish ‘primitive’ compared to birds, it is only with reference to the fact that fish-like vertebrates swam the oceans well before any bird soared in the sky. The term “derived” is also often used interchangeably with “advanced.”

Taxonomic relationships vs Phylogenetic relationships

Taxonomic nomenclature is a convenient way with which biologists and paleontologists group ancient organisms in order to be able to think about them. The modern nomenclature was devised by Carolus Linnaeus in 1758, based upon modern organisms, especially plants. As noted above, all taxonomic names above the species level are arbitrary. Organisms were classified in various groups based on similarities, but could not be in more than one group at a time (e.g. it is either a reptile or a bird, but not both).

From this has been derived the typical text-book image of evolution of vertebrates, from the most primitive (fishes) to the most advanced (mammals), and the notion that there ought to be intermediates like fish-ibian, repti-birds, and repti-mammals. This also suggests that from modern fish evolved modern amphibians evolved modern reptiles, evolved modern birds and mammals.

Phylogeny is the actual evolutionary relationships among different groups of organisms. There are no arbitrary divisions and classifications. The classic image of the “tree of life” is a very simple version of phylogeny. Today, biologists, botanists, and paleontologists use mathematical analysis of characteristics of organisms in order to work out phylogenies. The phylogeny appears very different from the taxonomic vision of organismal relationships.

Importantly, groups are united based on shared “derived” characteristics. That is, groups of organisms are distinguished from each other on the basis of new traits never before seen. Sometimes, the result is that groups considered distinct by Linnaen taxonomy are nested within one another.

Above is a simple phylogeny for vertebrates. All vertebrates are united by having vertebrae. The red lines are the evolutionary relationships among various groups of vertebrates. As one moves upward along any of these evolutionary lines, one moves toward more advanced species. The splits between groups occur among the most primitive members of the groups. For example, the first amphibians lie on the phylogeny at the point labeled “2” which represents the origin of terrestrial locomotion. These first amphibians, while by definition are amphibians, are not the modern, advanced amphibians that we see today. These first amphibians evolved from primitive fishes, which are also unlike any fish we have today.

Notice that birds and mammals and dinosaurs lie nested within other animals labeled reptiles. So birds and mammals are “reptiles,” but are distinguished from other reptiles based on characteristics of the skull (mammals) and by the ability to fly (birds). There is overlap among dinosaurs, birds, and reptiles. Phylogenies allow for one species to belong to more than one group.

Shown above are the positions on the phylogeny where the intermediated forms between the major classes would exist. Note that these are not at the tips of the evolutionary lines (modern forms) but lower on the phylogeny. The transitions occur from primitive members of one group into primitive members of another group. We do not draw frog’s legs on a trout and say this is what the transitional species between fish and amphibians looked like. We do not imagine a turtle with wings and call that the transition between reptiles and birds. (And we most assuredly do not look at a duck-billed platypus and call it a transition between birds and mammals, despite what I’ve seen published at times in the creationist literature.)

]]>Why “Intelligent Design” (ID) is not scienceWed, 01 Mar 2006 16:32:00 EDTinfo@csicop.org ()http://www.csicop.org/specialarticles/show/why_intelligent_design_id_is_not_science
http://www.csicop.org/specialarticles/show/why_intelligent_design_id_is_not_scienceScience is a tool used to describe our world, to understand why the world is the way it is, and to predict what the outcome of a mixture of characteristics may be. Science attempts to do this by studying only phenomena that are “material,” meaning countable, measurable, visible, tangible things, and by making the fewest assumptions possible. By being this way, scientists hope to eliminate faulty thinking and conclusions due to matters of opinion, professional conflict, personal experience, or biased knowledge (among other things).

Scientists approach their work by asking testable questions (hypotheses), running the tests (experiments), and by always providing within the hypothesis some means by which the hypothesis can be unequivocally disproved. Most experiments test the predictive power of the hypothesis: “If I mix chemical A and chemical B, I should get chemical C and a flash of light”, or “People who hate tomatoes also hate ketchup.”

In their experiments, scientists seek to validate their hypotheses — that is, to make observations that support their hypothesis and never once observe the evidence that disproves their hypothesis. If ever, even for a microsecond, that one thing that disproves the hypothesis is observed, then the whole hypothesis has been shown to be false. At this point, the scientist starts over with a new or revised hypothesis.

The most important point is that only one tiny little event can falsify a hypothesis: “I got chemical D” or “This person who hates tomatoes absolutely loves ketchup.” However, absolute proof can never be achieved, since there is always the chance that the single falsifying observation may have been missed.

If a hypothesis is subjected to test after test over many years and by many different people and does not fail, it will most likely be elevated to the level of “Theory.” The term “Theory” is science-ese for “we are pretty darn sure this is absolutely true, but since absolute proof is impossible by the nature of science, we’ll just call it something besides ‘absolute truth.’” This is basic scientific honesty; you can’t run every experiment or make every observation.

One of the most harassed theories today is the Theory of Evolution, which posits that all organisms on this planet are related through a common ancestor, and that it is gradual change over extreme spans of time that accounts for the diversity of species today. With this theory, we can predict and understand how and why organisms behave the way they do. If a person wants to understand why dogs, wolves, and coyotes are capable of interbreeding, but they generally don’t, one only has to look to evolution. To understand why birds’ “knees” bend backward — look to evolution. Why do we sometimes, when we’re particularly upset, find ourselves behaving like apes, and what can we do about it — turn to evolution. How can DNA from a virus infect a human cell — we’re talking evolution.

As noted earlier, science restricts itself to material knowledge. And it seeks to develop hypotheses that will assist us in understanding and predicting the nature of our world. Recently, the concept of “Intelligent Design” (ID) as been brought forward as an alternative “theory” explaining the origin of the diversity of life on Earth. The key to ID is the notion that many of the basic parts that all organisms share are too complex to have arisen from gradual change. ID proposes that some external agent or intelligence is responsible for making these critical bits.

But is ID Science? Should it be taught in a science classroom alongside the Theory of Evolution?

Well, can it be tested? Are there falsifying observations? ID could potentially be disproved by observing a more primitive intermediate form of some part that has been touted as ‘too complex’ to be natural. But then, the individual running the ID experiment can alter his hypothesis to say that this new structure is that which was installed by the Intelligent Designer. Because of this, there is no part of ID that can be unequivocally falsified by material science.

The second part of ID calls for an external Designer. This idea is neither fully supported nor fully falsified by material observation. There is no scientific way to test for the presence or absence of the Designer, as the Designer is defined as unobservable, or at least, only observable by a chosen few.

One of the most important characteristics of scientific hypotheses and theories is the predictive power they provide. ID does not offer any new explanation or observation about these complex structures that the Theory of Evolution does not already provide. The observation that some structures in organisms are too complex to have originated from gradual change will not help scientists to develop a better antibiotic, for example. In fact, the idea that “some things are too complex” is anti-scientific, since it seems to suggest that we shouldn’t try to understand the origins of the complex structures. ID discourages us from looking and asking questions. True science, however, moves on. If it is later found to be the case that some structures in organisms do not have more primitive counterparts, science will observe and recognize this fact, and the new knowledge will be incorporated into evolutionary theory.

ID is not a scientific theory and should not be taught alongside the Theory of Evolution. It offers nothing to help students understand how science works. It is merely a statement of how complex life seems to be — not even worth an hour of classroom time.